Mid-Infrared Photometry and Spectra of Three High-Mass Protostellar Candidates at IRAS 18151–1208 and IRAS 20343+4129

We present arcsecond-scale mid-IR photometry (in the 10.5 μm N band and at 24.8 μm), and low-resolution spectra in the N band (R ≃ 100) of a candidate high-mass protostellar object (HMPO) in IRAS 18151–1208 and of two HMPO candidates in IRAS 20343+4129, IRS 1 and IRS 3. In addition, we present high-resolution mid-IR spectra (R ≃ 80,000) of the two HMPO candidates in IRAS 20343+4129. These data are fitted with simple models to estimate the masses of gas and dust associated with the mid-IR-emitting clumps, the column densities of overlying absorbing dust and gas, the luminosities of the HMPO candidates, and the likely spectral type of the HMPO candidate for which [Ne II] 12.8 μm emission was detected (IRAS 20343+4129 IRS 3). We suggest that IRAS 18151–1208 is a pre-ultracompact H II region HMPO, IRAS 20343+4129 IRS 1 is an embedded young stellar object with the luminosity of a B3 star, and IRAS 20343+4129 IRS 3 is a B2 ZAMS star that has formed an ultracompact H II region and disrupted its natal envelope.

[1]  P. Ho,et al.  Unveiling the nature and interaction of the intermediate/high-mass YSOs in IRAS 20343+4129 , 2007, 0708.3748.

[2]  J. Alves,et al.  The Infrared Extinction Law at Extreme Depth in a Dark Cloud Core , 2007, 0704.3203.

[3]  G. Fuller,et al.  A survey of OH masers towards high mass protostellar objects , 2007, astro-ph/0701652.

[4]  J. Buizer.  The Complex Mid-Infrared Structure at the Heart of IRAS 20126+4104 , 2006, astro-ph/0611559.

[5]  R. Indebetouw,et al.  Interpreting Spectral Energy Distributions from Young Stellar Objects. II. Fitting Observed SEDs Using a Large Grid of Precomputed Models , 2006, astro-ph/0612690.

[6]  J. Buizer.  The Remarkable Mid-Infrared Jet of the Massive Young Stellar Object G35.20–0.74 , 2006, astro-ph/0603428.

[7]  Joseph D. Adams,et al.  Mid-infrared emission at photodissociation regions in the orion nebula , 2006 .

[8]  Three-dimensional Models of Embedded High-Mass Stars: Effects of a Clumpy Circumstellar Medium , 2005, astro-ph/0509073.

[9]  Harvard-Smithsonian Center for Astrophysics,et al.  Observations and Modeling of the 2-25 μm Emission from High-Mass Protostellar Object Candidates , 2005 .

[10]  G. Fuller,et al.  The Direct Detection of a (Proto)Binary/Disk System in IRAS 20126+4104 , 2005, astro-ph/0508342.

[11]  J. Buizer,et al.  Investigating the Nature of the Dust Emission around Massive Protostar NGC 7538 IRS 1: Circumstellar Disk and Outflow? , 2005, astro-ph/0506474.

[12]  D. Jaffe,et al.  Mass Flows in Cometary Ultracompact H II Regions , 2005, astro-ph/0506116.

[13]  C. Telesco,et al.  Observations of Massive Star-Forming Regions with Water Masers: Mid-Infrared Imaging , 2004, astro-ph/0410630.

[14]  R. Indebetouw,et al.  Two-Dimensional Radiative Transfer in Protostellar Envelopes. III. Effects of Stellar Temperature , 2004 .

[15]  W. Varricatt,et al.  Collimated molecular jets from high-mass young stars: IRAS 18151-1208. , 2004 .

[16]  T. K. Sridharan,et al.  The circumstellar environments of high-mass protostellar objects , 2004, Astronomy & Astrophysics.

[17]  D. Lester,et al.  High-Resolution Far-Infrared Observations and Models of the Star Formation Core of G34.3+0.2C , 2004 .

[18]  K. Wood,et al.  Two-dimensional Radiative Transfer in Protostellar Envelopes. II. An Evolutionary Sequence , 2003, astro-ph/0309007.

[19]  S. Price,et al.  A Uniform Database of 2.4-45.4 Micron Spectra from the Infrared Space Observatory Short Wavelength Spectrometer , 2003 .

[20]  B. Draine.  INTERSTELLAR DUST GRAINS , 2003, astro-ph/0304489.

[21]  M. Wolff,et al.  Two-dimensional Radiative Transfer in Protostellar Envelopes. I. Effects of Geometry on Class I Sources , 2003, astro-ph/0303479.

[22]  Joseph L. Hora,et al.  MIRSI: a Mid-InfraRed Spectrometer and Imager , 2000, SPIE Astronomical Telescopes + Instrumentation.

[23]  C. Davis,et al.  H2 Emission around Massive Young Stellar Objects with Outflows , 2002 .

[24]  G. Fazio,et al.  Mid-Infrared Observations of M17 , 2002 .

[25]  K. Menten,et al.  CH3OH and H2O masers in high-mass star-forming regions , 2002, astro-ph/0205348.

[26]  P. Godfrey,et al.  Modelling methanol and hydroxyl masers in star-forming regions , 2002 .

[27]  K. Menten,et al.  Massive molecular outflows , 2001, astro-ph/0112508.

[28]  T. K. Sridharan,et al.  High-Mass Proto-Stellar Candidates - II : Density structure from dust continuum and CS emission , 2001, astro-ph/0110370.

[29]  D. Jaffe,et al.  TEXES: A Sensitive High‐Resolution Grating Spectrograph for the Mid‐Infrared , 2001, astro-ph/0110521.

[30]  K. Menten,et al.  High-Mass Protostellar Candidates. I. The Sample and Initial Results , 2001, astro-ph/0110363.

[31]  M. Claussen,et al.  Evidence for a Solar System-Size Accretion Disk Around the Massive Protostar G192.16-3.82 , 2001, Science.

[32]  H. Kataza,et al.  High-Resolution Mid-Infrared Imaging and Spectroscopic Observations of a Massive Star Forming Region W51 IRS 2 , 2001 .

[33]  G. Anglada,et al.  Radio Spectral Indices of the Powering Sources of Outflows , 2001 .

[34]  G. Fazio,et al.  Narrowband Mid-Infrared Images and Models of the H II Complex G34.3+0.2 , 2000 .

[35]  G. Blake,et al.  Structure and Evolution of the Envelopes of Deeply Embedded Massive Young Stars , 2000, astro-ph/0001527.

[36]  G. Blake,et al.  The Impact of the Massive Young Star GL 2591 on Its Circumstellar Material: Temperature, Density, and Velocity Structure , 1999, astro-ph/9905035.

[37]  J. Krolik.  Active Galactic Nuclei , 1998 .

[38]  G. Ferland,et al.  CLOUDY 90: Numerical Simulation of Plasmas and Their Spectra , 1998 .

[39]  J. Hackwell,et al.  Infrared Spectroscopy of Ultracompact H II Regions , 1998 .

[40]  M. Campbell,et al.  High-resolution far-infrared observations and radiative-transfer models of W3 IRS 4 and IRS 5 , 1995 .

[41]  Jesse D. Bregman,et al.  Spectral Irradiance Calibration in the Infrared.IV. 1.2-35 micron spectra of six standard stars , 1995 .

[42]  Frank H. Shu,et al.  Photoevaporation of Disks around Massive Stars and Application to Ultracompact H II Regions , 1994 .

[43]  C. Engelke.  Analytic approximations to the 2-60 microns infrared continua for standard calibration stars - With application to the calibration of spectroscopy and photometry, and the determination of effective temperature and angular size from IR measurements , 1992 .

[44]  S. Kwok,et al.  New low-resolution spectrometer spectra for IRAS sources , 1991 .

[45]  D. Osterbrock,et al.  Book-Review - Astrophysics of Gaseous Nebulae and Active Galactic Nuclei , 1989 .

[46]  D. Osterbrock,et al.  Astrophysics of Gaseous Nebulae and Active Galactic Nuclei , 1989 .

[47]  K. Krisciunas,et al.  ATMOSPHERIC EXTINCTION AND NIGHT-SKY BRIGHTNESS AT MAUNA-KEA. , 1987 .

[48]  D. Osterbrock.  Active Galactic Nuclei a , 1984 .

[49]  T. Geballe,et al.  Infrared emission line studies of the structure and excitation of H II regions , 1982 .

[50]  N. Panagia,et al.  Some physical parameters of early-type stars , 1973 .